Better comprehension of the processes involved in the maintenance of oral health requires the understanding of the salivary components responsible for the protection of hard and soft oral tissues from physical, chemical and microbial damage. It is believed now that salivary secretory proteins play significant role in the maintenance of oral health. Many protective properties of salivary secretory proteins are acquired through the post- translational modifications such as sulfation and acylation. Although sulfation has been well accepted for its significant role in the processing of secretory proteins, no investigation has so far been directed towards its regulation. Thus, our major effort in this project is focussed on the regulation of tyrosine sulfation and glycoprotein sulfation in salivary glands. Since lipids are the structural components of biological membranes and that the two sulfotransferases involved in the sulfation of salivary proteins are integral membrane proteins of Golgi, the effect of lipids on sulfotransferases will be investigated. Our preliminary studies suggest that the charges present in lipids could be responsible for their effectiveness, we will investigate the effect of polyelectrolytes on sulfotransferases. The effect of sphingosine on the secretion of salivary proteins will be studied in the isolated salivary cells. Furthermore, since sphingosine has been shown to regulate the activities of protein kinase C and phospholipase, in addition to its action on sulfotransferases, specific inhibitors of these two enzymes will be used to differentiate the sphingosine regulation of sulfation from its effect mediated through the changes in those two enzymes.The results of this project should help in understanding the regulation of the sulfotransferases involved in salivary sulfoprotein processing which could be related to sulfoproteins in the pathology of oral disease.